In the bowl of an electric mixer, cream together cream cheese, vanilla and powdered sugar until smooth.
Add pumpkin puree and mix well, scraping down the sides in between.
Fold in 6 crushed Oreos and 2 c. whipped topping.
Spread in prepared Oreo crust. Cover and refrigerate at least 4 hours and overnight, if possible.
Just before serving, spread the rest of the 8 oz. tub of whipped topping in the center of the pie, then crush about 3 more Oreos and sprinkle those on the whipped topping. Insert whole Oreos around the pie for garnish and serve.